ugoira
Ugoira is a custom animation format used by Pixiv. A Ugoira is a Zip file of images, played back using a custom Javascript player.
To upload a Ugoira to Danbooru, paste the Pixiv URL into the source field on the upload page, or upload using the bookmarklet.
To download a Ugoira from Pixiv, you can use Pixiv Toolkit or gallery-dl. Ugoiras downloaded this way can also be uploaded to Danbooru.
Technically, a Ugoira consists of Zip file containing each frame in JPEG or PNG format, and a separate JSON file containing the delay between each frame. Since each frame has a separate delay, it's possible for a Ugoira to have a variable frame rate. A custom Javascript player is used to play animations back. Since the JSON file containing the frame delays is separate from the Zip file containing the images, saving raw Ugoiras and playing them outside of a browser is difficult.
Ugoira is a custom format exclusive to Pixiv. Animations from other sites cannot be Ugoira.
Ugoira is often considered inferior to animations found on other sites due to Pixiv's limitations on uploading GIFs or MP4 videos. As a result, artists may convert their animations to GIFs before uploading, introducing dithering and/or color banding, and Pixiv's recompression process can introduce additional JPEG artifacts, affecting the overall quality of Ugoira animations.
另请参见
This tag implicates animated (learn more).
要将 Ugoira 上传到 Danbooru，请将 Pixiv URL 粘贴到上传页面上的源字段中，或使用书签进行上传。
要从 Pixiv 下载 Ugoira，您可以使用 Pixiv Toolkit 或 gallery-dl。通过这种方式下载的 Ugoiras 也可以上传到 Danbooru。
从技术上讲，Ugoira 由包含 JPEG 或 PNG 格式的每个帧的 Zip 文件和包含每个帧之间的延迟的单独 JSON 文件组成。由于每一帧都有单独的延迟，因此 Ugoira 可能具有可变的帧速率。自定义 Javascript 播放器用于播放动画。由于包含帧延迟的 JSON 文件与包含图像的 Zip 文件是分开的，因此保存原始 Ugoiras 并在浏览器之外播放它们很困难。
Ugoira 是 Pixiv 独有的自定义格式。来自其他网站的动画不能是 Ugoira。
由于 Pixiv 对上传 GIF 或 MP4 视频的限制，Ugoira 通常被认为不如其他网站上的动画。因此，艺术家可能会在上传之前将其动画转换为 GIF，从而引入抖动和/或色带，而 Pixiv 的再压缩过程可能会引入额外的 JPEG 伪像，从而影响 Ugoira 动画的整体质量。